[FFmpeg-devel] [PATCH 1/3] nutdec: fix infinite resync loops

[Michael Niedermayer]

On Wed, May 20, 2015 at 04:34:49PM +0200, Andreas Cadhalpun wrote:
> On 20.05.2015 02:00, Michael Niedermayer wrote:
> > On Wed, May 20, 2015 at 12:49:49AM +0200, Andreas Cadhalpun wrote:
> >> nut->last_syncpoint_pos doesn't necessarily change between resync
> >> attempts, so find_any_startcode can return the same startcode again.
> >>
> >> Thus remember where the last resync happened and don't try to resync
> >> before that.
> >>
> >> This can't be done locally in nut_read_packet, because this wouldn't
> >> prevent infinite resync loops, where after the resync a packet is
> >> returned and while reading a following packet the resync happens again.
> >>
> >> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
> >> ---
> >>  libavformat/nut.h    | 1 +
> >>  libavformat/nutdec.c | 3 ++-
> >>  2 files changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/libavformat/nut.h b/libavformat/nut.h
> >> index 943081c..0c678a5 100644
> >> --- a/libavformat/nut.h
> >> +++ b/libavformat/nut.h
> >> @@ -102,6 +102,7 @@ typedef struct NUTContext {
> >>      unsigned int max_distance;
> >>      unsigned int time_base_count;
> >>      int64_t last_syncpoint_pos;
> >> +    int64_t last_resync_pos;
> > 
> > i think this and possibly some other fields must be reset on seeking
> > otherwise resync after seeking could break
> 
> Attached patch resets last_resync_pos in read_seek.
> I'm not sure if last_syncpoint_pos also has to be reset or if the
> syncpoint handling at the end of read_seek is already enough.
> 
> Best regards,
> Andreas
> 

>  nut.h    |    1 +
>  nutdec.c |    5 ++++-
>  2 files changed, 5 insertions(+), 1 deletion(-)
> b32d36842ae472ac23d4445d35cee09c8a9adc46  0001-nutdec-fix-infinite-resync-loops.patch
> From 0b000f4463cfb8d40571fd0620ec5f536296ea1b Mon Sep 17 00:00:00 2001
> From: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
> Date: Wed, 20 May 2015 00:06:05 +0200
> Subject: [PATCH 1/3] nutdec: fix infinite resync loops

LGTM

thanks

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

While the State exists there can be no freedom; when there is freedom there
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